2 Answers
2

That file is supposed to be there (or under /usr/bin/[). It allows you to type, for instance, [ -f $HOME/.bashrc ] && echo ".bashrc exists", which is equivalent to test -f $HOME/.bashrc && echo ".bashrc exists".

Reality is a bit more complicated, since bash overrides /usr/bin/[ with its own [, so you can use the [ executable by providing a full path, /usr/bin/[ -f $HOME/.bashrc ] && echo ".bashrc exists".